Artificial line.



Y S. HOYT, F IBOKLYN, NEW YORK, ASSIGNOR T0 man' 'rnrfarnorm a' `aannemer:n COMPANY, ,a como'rrom or aw Yoan.

i Y ARTIFICIAL LINE.

merece.

, Toall wkom lt concern Be it known that I, RAY S. HoY'r, residin at Brooklyn, inthe county of `Kings an v State of New York, have invented certain Improvements .in Artificial Lines, of which the following isa specification.

My inventlon relates to an artificial line, and more particularly to an artificial line which closely simulates the impedance of a long uniform, that is a nonjloaded or a continuousl loaded, transnnsslon luie, over the range o telephomc frequencles.

It has been known hitherto that the impedance of a transmission line can be simulated to any desired degree of precision by constructing an artificial line consisting of a series of sections, each section containing an inductance element and a ,resistance element in series with the lineand a condenser in shunt across the line. Such an artificial line is a model'of the actual line, differingVv from the actual line only in that the electrical constants of the actual line areuniformly distributed while those of the artificial line are concentrated or lumped.

The .object of the present invention is to provide, as a suitable substitute for such model "of the actualline, a simple circuit arrangement, preferably a two-element structure, which shall simulate closely the im-4 pedance of the actual line.

In the accompanying drawin s, Figure 1 4 is a' diagram showing the arti cial line of my invention; 'and Fig. 2 is a diagram showing the artificial line of my invention connected to a transmission line.

As shown in Fig. 1, the artificial line of my present inventionconsists of a resistance elementRD and a condenser Cu connected in series with each other and having values determined in the manner hereinafter set forth. Fig. 2 shows said artificial line connected through its 'terminals l, 1 to a uniform'transmission line 2, 2. With the arrangement shown in Fig. 2, a short length of transmission line will behave like an infinitely long line with respect to a voltage impressed across the terminals 3, 3.

A well-known general formula for the impedance of along uniform line is:

In the above formula, K denotes the imi pedance; R, L,`G and C denote the distributed resistance, inductance, leakage conduct- Specication of Letters Patent.

ance and capacity length of line;

ing formula is:

@vg-filata) e Now the value of K as expressed by equa; tion (3) is precisely the impedance of a resistance R0 1 n series with a capacity C0 if It therefore follows that the impedance of R., in series with C0, when R0 and Co are de` termined by equations (4) and (5), is very closely equal to the impedance of the uniform transmission line. Equations (4) and (5) are then the design formulae for determining the values of the two elements R0 and C0 of this invention.

As an example of the application of my invention,let it be required to construct an -artificialline to simulate the impedance of Patented Jian. llt, '315916. Application med August 7,1915. seminaaalm.

respectively, per V unit il V `eoj` in which denotes the frequency cycles",

a long uniform transmission, having the following specications:-An aerial line, consisting of two parallel #8 B. W. G copper wires, having an inductance per mile-:0.00337 henries, a capacity per mile: 0.0092 1O8 farads, and a resistance per mile-:4.,1tfohms In such case L=0.00387 henries,"C=0.0092 10-a farads; and R: 4.14 ohms. By substitution in formulae (4) and (5) of these values of the line constants, R0=606 ohms and C0---2.69 106 farads.

An artificial line simulating the impedance of an actual uniform transmission line 'resistance element being land comprising resisten-ce and capacity ele- I and the value of said capacity element being approximately equal to R where L; and R denote thedistributedlin- In testimony whereof, I have signed my name tO this specification in the presence of two subscribing witnesses, this 4th day Of August 1915.

RAY s. HOYT,

lwitnesses: i

GEORGE E. FOLK, JOHN R. CARSON. 

